Digging machine for mining coal



Oct. 6, 1953 c. E. BERRY nxccmc MACHINE FOR MINING com.

' 4 Sheets-Sheet 1 Filed Feb. 4, 1950 fill I #333355 v izvenfa" aries EBer/y y 'CQMQP ul r. g

.lfforne yj Oct. 6, 1953 c. E. BERRY DIGGING MACHINE FOR MINING com.

4 Sheets-Sheet 2 Filed Feb. 4, 1950 Oct. 6, 1953 C. E. BERRY I DIGGING MACHINE FOR MINING COAL 4 Sheets-Sheet 3 Filed Feb. 4, 1950 nzzekzar rZe-s .ZLBerr Get. 6, 1953 c. E. BERRY 2,654,586

DIGGING MACHINE'FOR MINING COAL Patented Get. 6, 1953 UNITED STATES ATENT OFFICE DIGGING MACHINE FOB MINING COAL Application February 4, 1950, Serial No. 142,489

8 Claims.

My invention relates to a digging head for machines, particularly adapted to the mining of coal and materials of similar nature, my particular object being the production of a machine that will conduce to safety, increase production of coal, and promote more economical mining.

Heretofore, it has been common practice in mining coal to first undercut the coal, then bore or drill holes to receive explosives, then shoot or blast to break the coal from the solid, and then load, either by hand or mechanical means, onto conveyors, cars or other suitable means of transportation.

The nature of these operations permits only one operation to be performed at one time, and requires the movement of men and machines into and out of the working place with each operation, thereby causing loss of productive time.

This practice requires numerous machines which are non-productiv during considerable periods of time.

The use of explosives in the mine to break down the coal is known to have numerous disadvantages and hazards. The combination of cutting, drilling, shooting and loading produces finely divided dust particles which are hazardous to both life and property and objectionable to consumers of coal.

Heretofore, machines have been constructed to eliminate some of the objectionable features, but such machines all have numerous and known disadvantages. One of the most important of these is the finely divided dust particles, or fine slack, produced by machines using the cutting chain principle which, in effect, cuts or shears the coal from the solid, dragging and grinding the coal from the cut. Another disadvantage is the numerous moving parts, such as chains, links, pins, levers and wheels, which are subject to excessive wear. Some machines employ the wedge principle, others a shearing blade, and still others force bits or rods into the body of the coal to break it down. All these, and others, have one common disadvantage of requiring great quantities of power due to the fact that they work against the greatest strength of the coal, that is its shear and/or crushing resistance, and its great internal resistance due to internal compression of solid coal.

The structure of coal offers least resistance to impact force, as is readily demonstrated by dropping coal onto any solid surface.

Inspection of coal under a microscope shows that it contains minute cracks and crevices, and is composed of minute layers or laminations or of granular particles. In its natural form when surrounded by other coal or covered with rock or overburden, these laminations and particles are bound together with considerable compression and offer great resistance to any penetration or disruption.

The exposed surface of coal, however, being relieved of such compression, immediately offers lower resistance. Such exposed surface has, in fact, a tendency to expand and crack along the lines of the minute cracks and iaminations.

This effect penetrates for some depth into the coal, the depth varying with the structure of the particular coal being considered. In general, however, most coals are easily chipped or penetrated, with very slight force, to a depth of threeeighths of an inch upward to one and one-half inches. This fact is readily proven by means of a testing machine designed to remove chips or sections of coal by means of impact force. Tests prove that the amount of force required does not increase in proportion to the amount of coal or section removed but that, as the depth of section is increased, the force required, per unit of coal, increases rapidly. This effect of chipping the exposed surface of coal with small force is further demonstrated by a man using a common coal pick. With very slight effort, and in fact with the weight of the pick alone, by directing the pick downward and outward in a circular motion, a small section or chip or particle of coal will be removed. Tests with such an impact machine show that one-half cubic inch of coal is readily removed, from average coals, with a force of ten foot pounds.

These considerations lend themselves to a convenient and economical method of mining coal, and my invention proposes to take advantage of the weakness of coal to resist impact force and of the lower resistance of the exposed surface of coal by providing a digging head with rotating and vibrating bits which will, by impact force, remove or separate a small thin section of coal from its exposed surface, removing said coal in the form of small lumps or chips and removing said coal in a continuous manner. The method of doing this will be shown as th description proceeds.

An object of this invention is to produce a machine which will permit continuous mining and thereby eliminate non-productive time.

Another object is to produce a machine which will do the work previously performed by several machines.

Another object is to produce a machine which will eliminate the use of explosives in the mine and thereby conduce safety.

Another object is to reduce the amount of fine coal, or dust, produced by prior mining methods.

Another object is to provide a machine which will mine a higher percentage of stoker, or peasize coal, which is most suitable for stokers or mechanical burning equipment.

Still another objectis to produce "a machine which will mine coal in a reasonably uniform size most readily handled by conveying equipment.

Another object is to provide a machine which will produce coal of a reasonably uniform size so that a minimum amountofcrushingorpother preparation is subsequently necessary.

A further object is to provide a machineiwvith a minimum number of Working and wearing parts, of simple construction.

These and other objects will be apparent from the following description, and: reference -to the attached drawings, in which:

Figure 1-is aplan =view showingmy improved form of-digging head applied to-1a -mining' machine, with the head i-n digging operation in-aa mine;

Figure'2 is an enlarged fragmentarydetailed section of the front en dof the miningamachine shown in Figure -1, .taken generallyalong the axis of rotation of the=digging head;

Figure 3 is an enlargeddetailed section'taken on line 3--3 of 'Figure Z;

Figure '4 is-a detailed? sectiontakenaonaline i"4 of Figure 2, drawn tothe'same scaleas-Figure 3;

Figure 5 is a side view of the frontend-of the machine, drawn to a-sl-ightly large'r scalethan Figure 2, but showing thedigging head arid elevating frame therefor adjusted to -a -higher digging level;

Figure 6 is a fragmentary detailed section of the digging head and 'immediately -assoeiated drive and-support -means 'ther'efor, taken'along the axis of rotation of said 'digg-ing head an'd drawn to a largerscale than Figure 2;

Figure l is-a detailed front View of the universally mounted support for the rear endof the digging head;

Figure 8 is-aside view of the-parts shown-"in Figure '7;

I Figure?) is a detailed faceview of the universal joint fordriving the outer hollowshaft of the digging head;

Figure 10 is a side-view of *the' part-shown in Figure 9;

Figure 11 is a detailed face view ofthe rubber insert ring forming part of the universal joint shown in I Figures '9 and 10 Figure 12 is a detailed section through the rotary digging head, taken on line I2I2= of Figure 6; and

Figure l3-is a diagrammatic-view 'illustrating the principle of operation of 'the rotary' digging head as it removes the coal from the working f-ace.

Referring now to the embodiments of my invention, and first to details of constructionof the digging head which: forms the principalfeature of my invention, I indicates a rotatable cylindrical shelltoxwhichiare attached a plurality .of digging bits -.2,12a projecting-'from the sides and closed front wall thereof. fi is-an offcenter-weight attachedito a shaft d. -A: tubular shaftw5 isv attached to the: inner: end of shell I and to a flexible shaft coupling 6. Bearings l and dim the shell' I ;and hollow shaitl5 .support fshaft 4. Shaft 4 is attached to flexible shaft coupling indicated generally at 9. It is apparent that rotation of this ofi-center Weight 3 will create vibration, and that said Vibration will be transmitted to the shell I and to the adjacent parts of the machine.

The tubular shaft 5 is supported at its rear end by the annular bearing (Lfdrming part of a universal joint type support indicated generally at Ii, so that vibration set up in the shell I by the weight 3 will terminate at the common center lineofthe universal support I I and flexible shaft couplings 6 and 9 and will not be transmitted to -'other bear-ings,gearings, motors and their suparms I I a with a sliding fit. Entrie -form herein,

three tubular arms 2 I13 :are provided adisposedzin planes substantially .at right angles to ze'acl'r other 'aboutshaft fi, with .one armr above the'bearing I2 and the two other arms at opposite sides thereof. "said arms are connectedattheinrear en'ds to frame members lfiilaand 1H fermingipart of an elevating-frame or support indicatedagenerally at 3i, which"will' hereinafterxbe more 'iu l ly described.

"Springs .15 aresprovidedi-to' ifit overieachiefuth arms I 3, one end of each such spring being-:seated: against the end :of armr M and :th'erother end being-seated against a nut t6 threadedzon arm 13. It is evident from thisconstructionthat adjustment of the nut I 6 will change .the com-pression=of spring I 5 and therebypontrel orfdamper the vibration create d by theeif cent'er weight 3 with respect to the -main s'upporting -structure for the digging head.

In-add'itior -a fourth armldw extends forwardly froman elevating-frame 31, which will presently be described in detail. In theferm she'wn, the arm Me has a pair of uprightsprings4 5a, Ita in-supporting engagement beneaththe bearin'g I 2--to provide -a"iioatin'g s'upport for the digging head. A thrust collar I2a is fixed as by weldingon the shaft' E in engagement Wi-th'the front en'd of bearing I2.

The tubular shaft ia is connected through-e flexible-coupling, indicated generally'at t to a tubular shaft i7- rotatably mounted on the niobile base 3'? and driven through power -means thereon, aswill presently" bedescribed.

Rotation-of the tubular shaft'i will-furnish rotary motion to the shellfra-me I and bits 2, causing the bitsi-to rotate around the fixedaxis A--"A-of Figure =8.

The shaft 4, on which the'weight' tis keyed, is con neeted I through a flex ible coupling, indicated generally at- 9, to a' driven' shaft I8. As-will beseen "i-nFigures-G, 9,"l0=an'd IL the-fieXibIe couplin e is formed-by tQnguesEa-a'nd l'ia'forming -parts, respectively, of'oellars' eb and I! it fixed totheabutting endsof the tubular shafts and I1, and an 'in-termediate' -rubber "ring ta radially extending spoke fibgfi'bfittihg between adjacent tongues 5a and I'm. The flexible OOHDIlIlgIQ consists of inter-fitting tonguesi and I'8a forming parts'of co llars 412 and "i'fic fixe'd to the abutting endsor shafts and I 8, andintermedia-te rubber ring 9a, similar to but smaller than ring-i6a of couplings-16;interposedbetween adjacent; t gues do and. Ita of "coupling-d.

Many conventional methods for movably supporting the rotary shell frame and for driving the shafts if and it may be provided. In the illustrative form of supporting and driving mechanism shown herein, a structure very similar to conventional supporting means for kerfcutting machines is employed, including a base frame 35 having a turntable 36 mounted thereon and an elevating frame 3'? vertically adjustable on the turntable, with the digging mechanism connected to, and projecting from, the front end of said elevating frame.

The base frame 35 may, as usual, be provided with a pair of endless tread supports ill, it along opposite sides thereof, driven from motors M, ii as usual, through suitable gearing, indicated generally at 42, at the rear end of said base frame.

The turntable 36 is pivoted about an annular upstanding bearing to disposed toward the front of the base frame. Power means for rotating the turntable may consist, as usual, of a motor 45, herein of the hydraulic type, connected by intermediate gearing, indicated generally at 4?, to a spur gear 48 having teeth meshing with peripheral teeth surrounding the turntable.

The elevating mechanism for the elevating frame 3? consists of four upright hydraulic cylinders G, 56 mounted on the upper face of the turntable at widely spaced points and projecting upwardly through apertures 49 in the elevating frame 3'5 (see Figure 3). Said hydraulic cylinders have pistons 5|, 5i projecting through their upper ends and connected to L-shaped supporting brackets 52, '52 which depend along the sides of the cylinders and are connected to the bottom plate 37a of the elevating frame 3? adjacent the corners thereof.

The frame members 3b, to which the laterally extending arms it, it of the digging element are connected, is fixed to the front end of the bottom plate 37a of the elevating frame 37. The frame member ti, to which the upright arm It is connected, consists of a bracket fixed to the top of a cylindrical bearing member 55 in which hollow shaft i? is journalled. The fourth arm lea extends forwardly from the bottom plate 87a and is cut away at 55 to accommodate the lower part of universal joint ii (see Figure 2).

The frame members 39 also support the universal joint member, indicated generally at H, therebetween on horizontally extendin trunnions 5'1, 5?. Said universal joint member H includes an outer annular member 58 with a second circular member 59- connected thereto by upright trunnions 69, bit. The inner universal joint member has a plurality of forwardly projecting arms 6i, ti connected to the bearing l0, previously mentioned, in which the tubular shaft 5 of the digging arm is rotatably mounted. As will be seen from Figure 6, the universal joint H, which supports the bearing ii], the universal joint 6 which connects the tubular shaft 5 with its drive shaft H, and the coupling which connects the inner shaft 3 with its drive shaft it, all are in mutual registering relation with each other longitudinally of the shafts named, so that the tubular shaft 55 and the inner drive shaft 4 are capable of limited universal tilting movement relative to the elevating frame 3?, under control of the arms id and Ma and spring I5, I be.

Independent drive means for the tubular shaft 5 and the inner drive shaft 4 consists of two electric motors 65 and t6 mounted on opposite sides of the elevating frame 31. The motor 65 for driving the inner shaft has an armature pinion 61 at its rear end, connected through suitable gear reduction mechanism, indicated generally at 68, in gear housing 69 to a gear lBd fixed on the rear end of shaft it which is connected to the shaft 4 through the universal joint 9, as previously described.

The second motor 65 for driving the tubular shaft ii has a motor pinion it at its rear end connected through suitable gear reduction mechanism, indicated generally at VI, to a gear 32 fixed on the rear end of the tubular shaft ll. Said tubular shaft ll extends forwardly and is connected to the tubular shaft 5 through the universal joint 6, as previously described.

The motors 65 and 66 are provided with independent current supply and controllers of any conventional form (not shown),-so that the two shafts and 5 may be driven independently of each other at difierent speeds and in the same or reverse directions, as desired.

Any suitable means for removing and loading out the coal cut away from the coal seam by the rotary digging head may be provided. In the illustrative form of loading out apparatus shown herein, the front end of the base frame 35 is provided with a plurality of radial spokes it connected to a circular guide member 75, which is concentric with the turntable axis, and also extends beyond the front portions of the endless trades it, flit. The turntable 36 has an arm at which extends forwardly beneath the arm Ma, with a depending portion ii normally in bearing engagement with the outer face of the guide member 75. An arcuate scraper $2 is pivotally connected by an upright pivot pin 83 to a lateral extension {is of depending portion 8 i. The scraper 82 has an arm 55 extending beyond its pivot pin and engaging the rear face of the lateral extension arm to, to hold the scraper in proper angular position as the turntable is swung in a counter-clockwise direction, as seen in Figure 1, so that the scraper follows closely behind the rotary digging member and gathers the coal fragments which have been dislodged from the coal face and deposited on the mine fioor.

When the turntable 36 is moving in a clockwise direction to return the cuttings head to a starting position to a subsequent pass of the rotary cutting head across the coal scam, the scraper arm may turn a limited amount about the pivot pin to assist in a relatively unimpeded return movement of the scraper to the starting position. As the digging proceeds toward the left-hand side of the room, the coal fragments gathered by the scraper will be moved toward the left side of the machine, in position to be loaded on the feeder head of a conventional shaker conveyor, indicated generally at 36. The details of construction of the shaker conveyor need not be further shown nor described, since it forms no part of the invention and other forms of loading devices may be used for removing the loose material from along the working face.

The use and operation of the digging head, as above described, is as follows:

Since the shell i of the digging head can be rotated by its drive motor 66 independentl of, and at a different speed than, the weight 3 driven from the motor 65, any desired vibration force can be obtained by selecting a suitable weight 3. after including and considering the weight of the shell l and its associated parts, and selecting a suitable speed of rotation for weight 3. Further, by means of properly coordinating tie speed of 7 rotation of the shell 1, with the-vibration created bytheweight 3, the bits 2 canbecaus'ed to. V1- brate a desired number of times per'revolution'of shell I.

This combination or rotating-and vibratingthe bits 2 is the force utilized in thepresent invention, to secure digging or mining action. The action of the digging head is best illustrated diagrammatically in Figure 13, which is shown by dotted line the outer-circumference of shell l and a single bit 2. The'centerof rotation of shell I, or axis A-A of Figure 6, is represented by the intersection of the vertical and horizontal center lines of Figure 13. For further illustration, a section of solid coal 2| is shown. With a given mass of the shell i and its associated parts, a given mass and relative speed of rotation of the weight 3, and-a given tension on the springs l5, the center of rotation of the shell I will oscillate about an approximate. path, indicated at 20, within fixed limits and with'controlled force. Also, the bit '2, or more exactly the point of bit 2, will oscillate on the dotted line 22.

Then, if the oscillation path of thebit-Z partly intersects the body of the coal, as further shown by the dotted line 22, the impact force o'f' the entire digging head will be delivered'to the coal. If this force be greater than the resistance of the coal, a section of coal, as indicated within the dotted line 22, will be removed.

If no other movement were now applied to the bit 2, it would merely continue to oscillate on the dotted line 22. I, therefore, provide for the rotation of the bit 2 around its axis AA, as previously shown. This rotation will bring the point of bit i successively-into new positions andcause it to come in contact with new sections of coal. As long as rotation and vibration con tinue, the bit will approximately follow the path I of dotted line 23, thereby digging or mining additional coal at each vibration.

By means of properly coordinating the rotation of the bits with the vibration-of the bits, coal can be dug or mined approximately along the line Ed, although it is not inten'dedto infer that coal will be removed inregular and uniform sections as shown, for'the coal will usually break out in highly irregular sections along the lines of lamination and fracture.

For illustrative purposes, only one bit has-been considered in connection with the diagram inFi'gure 13. The same digging effect is attained in practice, providing the shell, i has: aiplurality of digging bits 2, as shown inFigures 1,- 5 and 6.

While it is evident that the'digginghcad may beemployed as a drilling or boring tool by feeding it forwardly in the direction of its axis A--A, it will be understood that it operates most erfectively by swinging it in planes transverse to its axis AA thereto, or in any angle thereto, as indicated by the arrows in Figure 13.

Referring now more generally to the'use and operation of the digging headin. conjunction with the form. of supporting base32 shown in the drawings, said base is capable of introducing or sump-- ing the digging head and its associated parts-into the coal face in several different ways and at varying angles to the coal by manoeuvering thebase on its endless treads it with theturntable 3.8 disposed at varying angles with respect to the coal face.

In the illustrative method shown in Figure 1, the machine is employed for advancing a room or entry along a generally straight roomor entry with parallel side walls 9G, 90, which is formed by swinging the digging head and its supporting members through an arc of deg'rees from one side of the machineto the other, toforman arcuate working face 9| at the advaiicing end 0f the roomor entry. It will be understood that this mining operation is carried outlay-sumping the digging shell I when'it isdispos'ed at a right angle to the longitudinal axis of the machine as the. latter is positioned in the center of the room. In Figure '1, the initial sumping position of thedigging head is'shown indottedline's. By swinging the digging head under power inan arcuate "path-about the front end of the machine with the entire machine moved forwardly on itsendless treads d'li through adista'nce equal to that'which the workingface is to displace during one arcuate sweep, said digging head will remove the portion of the working 'facesl to'form a new arcuate working face, indicated at '52, forth-e full width of the room.

if theheight of the coal seam to be minedis, as may often be the case, greater than the diamet'er of the diggingshell i with'its'bits2, the arcuate swinging movement of'the shell! may be repeatedwith the elevating frame 31 raised-to a higher position, as indicated in Figure 5.

It will be understood that the initial sumping operation may also-be carried out with the digginghead disposed at less than a right angle to the line of advance of the machine as a whole, whena narrower room or-e'ntry is desired. In general, however, it will be borne in 'mind, as previously stated, that the-digging effect of the shell l .is-most eifective when the latter is advanced toward the coal in a general direction transverse to its normal axis of rotation. For this reason, it isobvious that best results will be attained by sumping the digging head in a working face when it is'at an appreciable angle to the direction in which the working face is being advanced, and thereafter swinging the digging head laterally across the working face.

This'app'lication is a continuation in part of my pending application Serial Number 39905, filed July 21,, 1948, now abandoned.

Although- I have shown and. described certain embodiments. for the. purpose described, it will be understood that I do not wish-to be limited to the exactconstruction:shownand described but that various changes-and modifications may be madex'without department from the spirit, and scope of-the invention as. defined. in 13116311)".- pended claims.

Iv claim:

1'. In a digging machinepa base, a rotary digg ing head includingan annular member having a plurality of'peripherally mounted, radially extending digging members thereon for engage ment with-- a working face, mean-s yieldably supporting said annularme'mber on said base, powermeans. on said base operatively connected through. said yieldable supporting means for rctating said annular member, an off-center weight mounted onand coaxial with said annular member for rotation independently 'there of, and" power means for driving said off-center weight at a speed different from said annular 1rznernber to impart vibratory motion tothe lat- 2'. The structure in accordance with claim 1, wherein the means for driving the off-center weight is also: mounted on the base and is operatively connected to said weight through the yieldable supporting means.

3. The structure in accordance with claim 1, wherein the yieldable supporting means for the rotary digging head and off-center weight includes a pivotal supporting structure permitting universal axial tilting movement of said digging head and weight relative to said base.

4. The structure in accordance with claim 3, wherein the yieldable supporting means includes a plurality of springs supported on said base and yieldably supporting said rotary digging head and weight beyond said pivotal connection in a plurality of angular directions relative to their normal axis of rotation.

5. The structure in accordance with claim 4, wherein the tension on said springs is adjustable to control the vibratory action of said rotary head.

6. A device of the class described comprising an outer shell having peripherally projecting digging bits, a tubular shaft for rotating said shell, an off-center weight rotatable within the outer shell to create vibration of the latter, a shaft within said tubular shaft to rotate said weight, a frame having supporting arms with adjustable compression means surrounding the outer tubular shaft intermediate its ends for controlling the vibration of said shell and tubular shaft, means on said frame for supporting the adjacent inner ends of said shafts including flexible shaft couplings coincident with said last- 10 named supporting means, and power-driving means on said frame for driving said shafts independently of each other through their respective flexible shaft couplings.

'7. A coal digging machine in accordance with claim 1, wherein power means is provided for feeding said annular member radially of its general axis of rotation.

8. A digging machine in accordance with claim 1, wherein the base is mounted on a movable frame for feeding movement in a direction transverse to the general axis of rotation of the rotary digging head, and power means is provided for moving said digging head relative to said frame for engaging the digging members on said head against a working face.

CHARLES EDWARD BERRY.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,797,024 Degenhardt et a1. Mar. 17, 1931 1,841,907 Newbaker Jan. 19, 1932 2,229,912 Baily Jan. 28, 1941 2,308,517 Konnerth Jan. 19, 1943 2,360,803 Steuerman Oct. 17, 1944 FOREIGN PATENTS Number Country Date 66,420 Norway July 5, 1943 365,168 Germany Dec. 9, 1922 

